The earliest magnetic recording devices were invented in the late 1800s and recorded sound on metal wire. Wire recorders employed a single recording transducer and became more practical and widely used in the late 1940s and into the 1950s. Subsequently, however, flat magnetic recording tape and recorders become more reliable and replaced wire recorders, particularly when recorders with two transducing elements were developed which could record/playback two parallel tracks on the magnetic tape, such as for a stereo recording.
Magnetic tape has also long been used to store computer data; current tape is typically being formatted with numerous parallel tracks. The corresponding data recorder includes a number transducing elements to read from or write to at least some of the tracks simultaneously. To access other tracks, a head assembly is moved laterally across the width of the tape. Servo tracks on the tape enable the transducing elements to maintain a proper position relative to the recording tracks (registration).
To increase the storage capacity of magnetic tape, the linear density of the data bits on the tape may be increased (by recording the bits closer together), the track density may be increased (by decreasing the width of the tracks to fit more tracks across a given tape width), or the length of the tape may be increased. Each of these methods eventually runs into technical barriers. For example, increasing the linear density requires that the media manufacturer be able to produce smaller bits without adversely affecting the signal-to-noise ratio. While 256-track tapes and recording devices capable of recording to and reading from them have been developed, increasing the track density still further requires even smaller transducing elements and the ability to keep them centered over the tracks. Finally, increasing the length of the tape requires that the thickness be decreased if the volume of the tape is to remain substantially constant. Consequently, new technology must be developed to manufacture thinner tape as well as to handle it in the tape drive.
An additional issue with magnetic tape is its environmental stability. As tracks become narrower, even minute changes in the position of a track may lead to track misregistration and the inability to record to or read from a track. While temperature fluctuations have always been an issue, thinner tape is more prone to warpage and other problems from even smaller temperature changes.
Consequently, a need remains for a magnetic recording format which is less susceptible to the problems described above.